The present invention relates to a sliding device for moving a seat in the lengthwise direction of a vehicle body, and in particular to a sliding device including a screw mechanism for moving a seat in the lengthwise direction of a vehicle body.
In a conventional sliding device for moving a seat in the lengthwise direction of a vehicle body which is disclosed in Japanese Patent Laid-open Print No. Sho64(1989)-9043 published in 1989 without examination, an upper rail for supporting a cushion with a recliner is mounted slidably on a lower rail which is secured to a floor of a vehicle body and is inter-locked with the lower rail. Within a space defined between the upper and the lower rails, a driving mechanism is accommodated which serves for moving the upper rail along the lower rail in the direction of the lengthwise one of the vehicle body. The driving mechanism includes a screw shaft which is so connected to the lower rail as to be rotatable and a nut threadably mounted on the screw shaft. The upper rail to which the nut is secured is set to be moved in the lengthwise direction of the vehicle body when a motor is turned on which is used for rotating the screw shaft.
However, in the foregoing structure, the screw shaft in the space on which the nut is treadably mounted is arranged in parallel with the inter-locked portion between the upper and the lower rails, which results in that the lower rail is compelled to be large in its width and a lower space defined between the cushion and the floor becomes narrow in the lateral direction of the vehicle body.